V Craig Jordan

..The question to be addressed is how we can amplify the new biology of oestrogen-induced apoptosis to create more complete responses in exhaustively antihormone treated metastatic breast cancer...

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..Tamoxifen and insecticides covalently bind to microsomal proteins. His contribution presaged worldwide studies of the induction of rat liver carcinogenesis by tamoxifen...

..Current clinical trials are addressing the value of aromatase inhibitors as chemopreventive agents for postmenopausal women...

..This knowledge would establish a practical approach to breast cancer chemoprevention for women at high risk (tamoxifen) and low risk (raloxifene)...

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..However, raloxifene has the beneficial side-effect of breast cancer prevention. These multifunction medicines provide proof of concept that novel molecules can be selectively targeted to diseases mediated by the endocrine system...

..New medicines now promise to provide chemoprevention strategies for women at risk for the development of many diseases...

..Changes in health care strategies to implement chemoprevention take time, but the evidence now suggests that chemoprevention has become a reality in clinical practice...

..Once our program is complete, the new knowledge will be available to translate to clinical care for the long-term maintenance of patients on antihormone therapy...

..Clearly these are particularly important issues not only for breast cancer treatment but also for selecting premenopausal women, at high risk for breast cancer, as candidates for chemoprevention using tamoxifen...

..This will allow the precise treatment of diseases that was previously considered impossible...

..Currently, the pharmaceutical industry is exploiting the SERM concept for all members of the nuclear receptor superfamily so that medicines can now be developed for diseases once thought impossible...

..This new discovery is currently being evaluated in clinical trials but it also solves the mystery mechanism of chemical therapy with estrogen noted by Haddow in the first Karnofsky lecture...

..Low-dose estrogen could be used to debulk patients followed by fulvestrant in a low estrogen environment (aromatase treatment) to maintain tumor control...

..quot; During the past 50 years, ideas about the value of antihormones translated effectively from the laboratory to improve clinical care, improve national survival rates, and significantly reduced the burden of cancer...

..In the present study, we evaluated whether buthionine sulfoximine (BSO), a potent inhibitor of glutathione (GSH) synthesis, is capable of sensitizing antihormone resistant MCF-7:2A cells to estradiol-induced apoptosis...

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..Further, flow cytometry showed that G-1 blocked MCF-7 cell cycle progression at the G(1) phase. Thus, GPR30 antagonizes growth of ERalpha-positive breast cancer and may represent a new target to combat this disease...

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..This paper will summarize the therapeutic options for anti-hormonal therapy, the role of anti-hormonal agents in advanced breast cancer, and adjuvant therapy and the current status of chemoprevention with selective ER modulators...

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..This finding has implications for the control of breast cancer with low-dose estrogen and other targeted therapeutic drugs...

..Therefore, these data indicate that E(2) induced apoptosis through ERS and inflammatory responses in advanced antihormone-resistant breast cancer...

..Better understanding of steroid receptors, their ligands, and the mechanisms through which they exert their effects will allow the correct treatment to be targeted to responsive tumors...

..These data and literature reports of the cyclical nature of anti-androgen/androgen responsiveness of prostate cancer growth, illustrate the generality of the evolution of anti-hormonal resistance in sex steroid-sensitive target tissues...

..This review article discusses the significant and continuing value of SERMs for the treatment of postmenopausal ER-positive breast cancer...

..Major efforts are therefore directed to make new SERMs with a better therapeutic profile and fewer side effects...

..Using available conformations of the ER liganded with 4OHTAM or diethylstilbestrol, the TPEs optimally occupy the 4OHTAM ER conformation that expresses Asp351...

..In conclusion, our findings establish CEACAM6 as a unique mediator of migration and invasion of drug resistant oestrogen-deprived breast cancer cells and suggest that this protein could be an important biomarker of metastasis...

..Together, these findings indicate that BZA is distinct from other SERMs in its ability to inhibit hormone-independent breast cancer cell growth and to regulate ERα and cyclin D1 expression in resistant cells...

..Physiologic concentrations of estradiol could potentially be used to induce apoptosis and tumor regression in tumors that have developed resistance to aromatase inhibitors...

..Another approach exploits the discovery that low dose estrogen will induce apoptosis in the SERM resistant breast cancers. Numerous clinical studies are addressing these issues...

..Overall, SERMs continue to fulfill their promise as appropriate medicines that target specific populations for the treatment and prevention of breast cancer...

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..Crosstalk among plasma membrane-localized ER, growth factor receptor signaling, and nuclear-localized ER provide further insights into antihormonal-resistant breast cancer...

..When resistant cells are killed, antihormonal therapy is once again effective. This new targeted approach to the treatment of metastatic breast cancer could open the door to novel approaches to treatment with drug combinations...

..This article reviews the development and role of the more common SERMs, tamoxifen and raloxifene. In addition, this paper will also highlight the emerging studies on phytoestrogens and their similarity and dissimilarity to SERMs...

..Moreover, expression of ERRs in other cancers and metabolic disorders may provide a targeted treatment strategy for these patients as well...

..Taken together these results reveal a new model for LAM pathogenesis in which activation of MEK-dependent pathways by E(2) leads to pulmonary metastasis via enhanced survival of detached tuberin-null cells...

..Additionally, two different classes of hormonal agents, the aromatase inhibitors and estrogen receptor down-regulators, which have no estrogen-like properties at any site, appear to be promising new treatments for advanced breast cancer...

..Alteration of either the side chain or its relationship with the negative charge at amino acid 351 controls the estrogen-like action at activating function 2b of the selective estrogen receptor modulator ERalpha complex...

..Therefore, based on our findings, GW5638 could be developed as a second line agent for advanced breast cancer patients and an important first line agent to evaluate as an adjuvant treatment or chemopreventive...

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..Treatment with raloxifene following 5 years of adjuvant tamoxifen may not further decrease breast cancer recurrence and may increase endometrial cancer incidence...

..CONCLUSIONS: In the current study, risk due to AH or LCIS was found to be the main predictor of being offered and accepting tamoxifen chemoprevention...

..In this study we investigated the in vitro effects of antiestrogens at different concentrations on vascular endothelial growth factor (VEGF) production in estrogen receptor (ER)-positive breast cancer cells...

..Emerging knowledge about the action of SERMs will provide clues for the design of mechanism-based medicines...

..Furthermore, two different classes of hormonal agents, the aromatase inhibitors and oestrogen-receptor downregulators, which have no oestrogen-like properties at any site, are promising new treatments for breast cancer...

..Three phases of tumor progression are described that involve increases in HER-2/neu expression, de-regulation of estrogen receptor expression and increases in apoptosis which in concert determine the phenotype of drug resistance to Tam...

..We conclude that endogenous ERbeta may not play a dominant role in the modulation of the tamoxifen ERalpha complex, or in the development of tamoxifen-stimulated resistant tumor growth...

..Based on the results, we suggest using an alternating treatment regimen, cycling antiestrogen with estrogen therapy to avoid drug-resistance...

..This minireview will describe the current strategies for the treatment and prevention of breast cancer and present emerging new concepts about the consequences of exhaustive antiestrogen treatment on therapeutic resistance...

..The future exploitation of these novel data will allow selective killing of cancer with fewer side effects for patients...

..CONCLUSION: Physiologic levels of estradiol induced regression of tamoxifen-stimulated breast cancer tumors, apparently by inducing the death receptor Fas and suppressing the antiapoptotic/prosurvival factors NF-kappaB and HER2/neu...

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..We conclude that the differential regulation of telomerase gene might be an important transition for tamoxifen resistance in T47D:A18 breast cancer cells...

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..A specific increase in the level of a single coactivator appears to enhance estrogen action with tamoxifen at some gene targets in uterine cells but not breast cells...

..Tamoxifen is approved for the reduction of breast cancer risk, and raloxifene has demonstrated a reduced risk of breast cancer in trials of older women with osteoporosis...

..It is now clear that strategies utilising aromatase inhibitors and selective oestrogen receptor modulators will provide much needed options for individualised treatments...

..These compounds will function as multifunctional medicines and will hold the promise of preventing breast and endometrial cancer, while providing the beneficial effects of preventing osteoporosis and coronary heart disease...

..However, 40 years ago, it was hard to imagine that a non-toxic targeted treatment for breast cancer could be developed at all...

..However, there is an evolution of drug resistance to anti-hormones. This is evidenced by a change in sensitivity to estrogen. The natural hormone no longer stimulated tumor growth but causes apoptosis and tumor regression...